This invention relates to .beta.-lactam antibiotics. In particular, it relates to monocyclic .beta.-lactam antibiotics which are 3.beta.-acylaminoazetidin-2-ones.
The penicillins and cephalosporins are well known .beta.-lactam antibiotics which are bicyclic compounds containing a fused ring system. The penicillins have the 4-membered .beta.-lactam ring fused to a thiazolidine ring while in the cephalosporins, the .beta.-lactam ring is fused to a dihydrothiazine ring. Monocyclic .beta.-lactam antibacterial compounds are less well known. The monocyclic .beta.-lactam antibiotic, nocardicin, has been recently discovered and is described in Belgium Pat. No. 830,934 and by H. Aoki, et al., 15th Interscience Conference on Antimicrobial Agents and Chemotherapy, Abst. No. 97, Sept. 1975.
Nocardicin has the following structural formula. ##STR2##
In view of the importance of .beta.-lactam antibiotics in the treatment of infectious diseases, considerable effort is directed by microbiologists and chemists to the discovery and development of other .beta.-lactam antibiotics which possess activity against a broader spectrum of microorganisms or which are more effective than the currently available antibiotics.